“…These questions have attracted the attention of many researchers over the past 40 years and there have been many theories or models for power in exchange networks proposed, including power dependence theory (Cook and Emerson, 1978;Cook and Yamagishi, 1992;Buskens and van de Rijt, 2008), Vulnerability theory (Cook et al, 1983;Cook et al, 1986), graph power index or GPI theory (Markovsky et al, 1988;Patton and Willer, 1990;Markovsky et al, 1993), expected value theory (Friedkin, 1992(Friedkin, , 1993Bonacich and Friedkin, 1998), core theory Bonacich, 1992, 1993;Bonacich andBienenstock, 1995, 1997), exchange-resistance theory , reciprocity theory (Skvoretz and Lovaglia, 1995), identity theory (Burke, 1997), and versions of network exchange theory, which include optimal seek theory (Simpson and Willer, 1999;Girard and Borch, 2003) and, most recently, domain analysis theory (Willer et al, 2012). In a systematic survey of predictions, van de Rijt and van Assen (2008: p. 260) restrict attention to four core theory, power dependence theory, expected value theory, and network exchange theorybecause "no theories have been investigated as much and received as much attention as these theories.…”